Four-stack cartridge magazine

ABSTRACT

A firearm magazine for holding four stacks of cartridges and successively positioning them for removal includes partitionseparated primary and secondary chambers each adapted for holding a double-stack in staggered relationship. The partition includes a divider pivotally mounted for vertical displacement to open the chambers for loading cartridges thereinto and rotational displacement to releasably retain the cartridges in the secondary chamber until the primary chamber is depleted. The divider is releasably blocked in the retaining position by a slide actuable by the follower in the primary chamber when depleted, to release the cartridges in the secondary chamber.

United States Patent 1345,771 10/1967 Silsby i 42/50 Primary Examiner-Benjamin A. Borchelt Assistant E.tamincr-C. Ti Jordan Attorneys-Harry M. Saragovitz Edward J. Kelly Herbert Berl and Albert E. Arnold, .Ir.

ABSTRACT: A firearm magazine for holding four stacks of cartridges and successively positioning them for removal includes partitiomseparated primary and secondary chambers each adapted for holding a double-stack in staggered relationship. The partition includes a divider pivotally mounted for vertical displacement to open the chambers for loading cartridges thereinto and rotational displacement to releasably retain the cartridges in the secondary chamber until the pri mary chamber is depleted. The divider is rcleasably blocked in the retaining position by a slide actuable by the follower in the primary chamber when depleted, to release the cartridges in the secondary chamberv PATENTED sun 4m 3.604142 SHEET 1 UP 2 iii \Ea mm P I INVENTOR ATTORNEYS PATENTEU SEP] 4 1971 SHEET 2 BF 2 INVENTOR Sinrfle Jlfiflslng .S EM

ATTORNEYS FOUR-STACK CARTRIDGE MAGAZINE The invention described herein may be manufactured. used, and licensed by or for the Government for governmental pur pose without the payment to me of any royalty thereon.

BACKGROUND OF THE INVENTION This invention relates to cartridge magazines for firearms and relates more particularly to magazines for holding the cartridges in multiple stacks and for successively positioning them for pickup by the reciprocal firearm bolt.

SUMMARY OF THE INVENTION Increasing the firepower available to the troops while maintaining the bulk of their equipment at a minimum is a continual aim of ordinance engineers. Towards that end, it is a principal object of this invention to provide for shoulder-type firearms a large capacity cartridge magazine of practical proportions in which four stacks of cartridges are separated into two chambers in double-stack staggered relationship by a partition and which includes self-contained means for successively releasing the cartridges from the four stacks to positions for pickup by the reciprocal firearm bolt.

It is a further object of this invention to provide such partition with a divider section which is mounted for pivotal displacement so as to be actuated vertically for loading the cartridges into the magazine and for rotatable displacement to releasably retain the cartridges in one chamber until those in the other chamber are stripped therefrom.

Further objects and advantages of the invention will be apparent from the following specification and the accompanying drawings which are for the purpose of illustration only.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a longitudinally crosssectioned view of the magazine, unloaded, mounted to a firearm receiver;

FIG. 2 is a view taken along line 2--2 of FIG. I but showing the relationship of the magazine members during the loading process;

FIG. 3 is a view taken along the line 3-3 of FIG. I with the magazine in the same condition as shown in FIG. 2;

FIG. 4 is a view similar to FIG. 2 but showing the magazine members when the final cartridge in the primary chamber is in position for pickup by the firearm bolt;

FIG. 5 is a view similar to FIG. 3 but with the magazine in the same condition as shown in FIG. 4;

FIG. 6 is a view similar to FIGS. 2 and 4 but showing the relationship of the magazine members when the cartridges in the secondary chamber are released for pickup by the firearm bolt; and

FIG. 7 is a view taken along line 7-7 of FIG. I.

DESCRIPTION OF A PREFERRED EMBODIMENT Shown in the figures is a firearm receiver I2 which houses a reciprocal bolt 14 and mounted to such receiver is a magazine 16 for holding a supply of cartridges l8 and successively positioning the cartridges for pickup by the bolt during the reciprocal travel thereof.

Magazine 16 includes a case 20 having a left side 22 the upper portion of which curves upwardly and inwardly to form a lip 24, and a right side 26 which is similarly formed with a lip 28. Lips 24 and 28 are spaced apart a distance greater than the diameter of cartridges 18 to form a mouth 30 in which the cartridges are successively positioned for pickup by bolt 14.

A partition 32 divides case 20 into a primary chamber 34 formed between the partition and left side 22, and a secondary chamber 36 formed between the partition and right side 26. Each of the chambers 34 and 36 is adapted to hold a double stack of cartridges [8 in staggered arrangement, as shown in FIG. 2. Partition 32 includes a fixed wall 38 and a divider 39 which is a movable, upper extension thereof. Divider 39 is provided with a tongue 40 that extends forwardly from the lower portion of the front end thereof and a tang 4] that extends oppositely from the lower portion of the rear end. Tongue 40 is loosely received by an aperture 42 in front end 43 of case 20 to mount the divider thereat for pivotal displacement about the tongue. Tang 41 is received by a vertical, closed end slot 44 in rear end 45 of case 20 to assist tongue 40 in mounting divider 39 for rotation about an internal axis defined by such tang and tongue and also to limit the pivotal displacement of the divider about an external axis, normal to such internal axis, between an upper operative position and a lower depressed position.

A finger 46 extends rearwardly from the upper portion of divider 39 through an opening 48 in rear end 45 of case 20 for a purpose to be described hereinafter. The vertical length of opening 48 is sufficient to permit uninterrupted displacement of finger 46 therein when divider 39 is pivoted between the operative and depressed positions. The top portion of opening 48, noted at 50, is wide enough to permit rotational displacement of divider 39 between a blocking position respective to secondary chamber 36, wherein it is in alignment with wall 38, as shown in FIG. 4, and a release position wherein it is rotated to the left, as shown in FIG. 6. Top portion 50 narrows down to form a lower pocket portion 52 which receives finger 46 when divider 39 is actuated to its depressed position. Opening 48 forms a left wall 54 which slants downwardly and to the right so that when finger 46 is displaced into pocket portion 52 the top of divider 39 is centrally located thereby between the blocking and release positions thereof, as noted in FIGS. 2 and 3, to facilitate the loading of cartridges I8 into case 20.

Divider 39 is formed with a planar left side 56 which, when the divider is in the blocking position, is parallel to vertical axis xx of case 20, and a right side 58 which curves upwardly and to the right, as shown in FIG. 4, to form an edge 60. When divider 39 is in the release position, as shown in FIG. 6, edge 60 is spaced from right side 26 the same distance that top left edge 6] of the divider is spaced from left side 22 when the divider is in the blocking position shown in FIG. 4. This space is smaller than the diameter of cartridges 18 so that when divider 39 is in the blocking position the top cartridge I8 in primary chamber 34 is prevented from passing upwardly between the divider and lip 24 but is permitted to extend far enough into mouth 30 for contact by stripper 62 on bolt I4 when moving to battery position. Also, edge 60 is positioned to block passage of cartridges I8 from secondary chamber 36 into mouth 30 and to hold the uppermost cartridge depressed suffciently so that stripper 64 on bolt I4 does not contact it during reciprocal travel. When divider 39 is displaced to the release position, as shown in FIG. 6, cartridges [8 in secondary chamber 36 are released so that the uppermost cartridge is held between edge 60 and right side 26 for pickup by bolt l4.

Cartridges 18 in primary chamber 34 are biased upwardly therein to mouth 30 by a spring-pressed follower 66. Such follower 66 comprises a top surface 68 which contacts the last cartridge I8 in primary chamber 34, a left side 70 and a right side 72. Left side 70 is contoured according to the curvature of left side 22 of case 30 and right side 72 is inclined to coincide with the inclination of divider 39 when in the release posi' tion. Left side 70 and right side 72 are so designed and related that follower 66 is permitted a predetermined amount of upward overtravel in primary chamber 34 after the last cartridge 18 therein is picked up by bolt 14 and before upper travel of the follower is stopped. A lug 74 extends outwardly from follower 66 through a vertical slot 76 in rear end 45 of case 20 and upward travel of the follower is stopped by contact of the lug with top 75 of slot 76. Cartridges 18 in secondary chamber 36 are pressed upwardly therein towards mouth 30 by a spring-pressed follower 77.

Fixedly attached to the outside surface of rear end 45 of case 20 as by spot welding is a block 78 which is provided in the inside with a slot 80 which has registry with slot 44 in the case and which is adapted for mounting a coiled spring 82 so as to press upwardly against tang 41 to bias divider 39 to its operative position. Block 78 is also provided in the inside with a channel 84 which has registry with slot 76 to receive the end of lug 74, and a recess 86 which communicates with the top end of such channel and which opens sideways to a cutout portion 88 that provides a clearance for opening 48, as shown in FIGS. 3 and 5. Recess 86 slidingly mounts for vertical displacement therein a slide 90 which is essentially rectangular in configuration and which is provided with a vertical slot 92 for receiving a protuberance 94 that extends forwardly from block 78. Contact of top side 96 of slot 92 with protuberance 94 limits downward displacement of slide 90 in recess 86 and a spring 98 disposed between the protuberance and bottom side 100 of the slot biases slide 90 to a downward blocking position. When slide 90 is in its blocking position, a tang 102 extending from the top thereof has contact with finger 46 to releasably block divider 39 in its blocking position. When fol lower 66 moves to its overtravel position, after the last cartridge 18 in primary chamber 34 is picked up by bolt 14, lug 74 presses against the bottom end of slide 90 to press it to its upper position. This moves tang 102 out of contact with finger 46 and thereby frees divider 39 for pivotal displacement to its release position by the bias of cartridges 18 in secondary chamber 36 against the curved right side 58 of divider 39 as the top cartridge 18 therein moves to mouth 30 ready for pickup by bolt 14.

OPERATION Cartridges 18 are loaded into magazine 16 by successively placing them into mouth 30 and then pressing them down against divider 39 toward one of the chambers 34 or 36. The downward pressure against divider 39 displaces it downward to its depressed position with the top thereof centered by the reception of finger 46 in pocket portion 52 of opening 48 so that with the curvature of sides 22 and 26 the top ends of chambers 34 and 36 are both opened simultaneously with sufficient clearance provided for passage of cartridges 18 past the divider into one of the chambers. When loading is completed, divider 39 is forced manually to the right where it is retained by slide 90 and cartridges in primary chamber 34 are thereby permitted to rise to where the top one is located in position for pickup by bolt 14 between the divider and left side 22. The loaded magazine 16 is attached to receiver 12 in the usual manner.

During operation of the supporting firearm, cartridges 18 are successively picked up by bolt 14 from primary chamber 34 in conventional manner. When the last cartridge 18 in primary chamber 34 is stripped therefrom by bolt 14, follower 66 rises in overtravel so that lug 74 thereon lifts slide 90 to release divider 39. The upward bias of cartridges 18 in secondary chamber 36 pushes divider 39 to its release position, freeing the cartridges in secondary chamber 36 for upward displacement therein ready for successive pickup by bolt 14.

I wish it to be understood that l do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

lclaim:

l. A cartridge magazine for a firearm having a reciprocal bolt comprising, a case divided into a primary chamber and a secondary chamber, each of said chambers being adapted to hold a double stack of cartridges in staggered arrangement, self-contained means for successively positioning the cartridges for pickup by the bolt, and a partition for separating said primary and secondary chambers, said partition including a divider section mounted to said case for pivotal displacement about one axis to a position opening said chamber simultaneously for loading the cartridges thereinto and for rotational displacement about another axis normal to said one axis to releasably retain the cartridges in said secondary chamber until those in said primary chamber are entirely removed therefrom.

2. The magazine as defined in claim 1 wherein said case comprises a first side related to said primary chamber and a second side related to said secondary chamber, said sides each including an upper portion curving upwardly and inwardly to form therebetween a mouth arranged to successively receive the cartridges from said chambers for pickup by the bolt, and including a spring-pressed follower disposed in each of said chambers for biasing the cartridges therein towards said mouth, a partition separating said primary and secondary chambers, a divider section of said partition displaceably mounted in said case for cooperation with said upper portions to successively position the cartridges in said primary chamber at said mouth for pickup by the bolt and simultaneously hold the cartridges in said secondary chamber away from contact by the bolt until those in said primary chamber are entirely removed therefrom and to open the adjacent ends of said compartments for loading the cartridge into, and means cooperating with said divider to release the cartridges from said secondary chamber for successive pickup by the bolt when those in said primary chamber are entirely removed therefrom.

3. The magazine as defined in claim 3 wherein said last means cooperating with said divider comprise a slide displaceably mounted on said case so as to releasably hold said divider in an operative position relative to said upper portions for retaining the cartridges in said secondary chamber until those in said primary chamber are entirely removed therefrom, and a lug on said follower in said primary chamber arranged to displace said slide for release of said divider when the last cartridge in said secondary chamber is picked up by the bolt to permit rotational displacement of said divider by the bias of the cartridges in said secondary chamber thcreagainst to release the cartridges therein for successive pickup by the bolt at said mouth.

4. The magazine as defined in claim 3 and including means for mounting said divider for pivotal displacement about one axis between the operative position and a lower depressed position and for rotational displacement about another axis normal to said one axis between a blocking position wherein the cartridges in said secondary chamber are blocked by said divider from displacement to said mouth for pickup by the bolt when said divider is also in the operative position and a release position wherein the cartridges in said secondary chamber are released by said divider for displacement to said mouth, spring means cooperating with said divider for biasing said divider to the operative position, a finger extending from said divider for reception by an opening in said case, an upper portion of said opening cooperating with said finger for limiting rotational displacement of said divider between the blocking and release positions when in the operative position, and a pocket portion of said opening disposed for receiving said finger when said divider is actuated to the depressed position by downward pressure of the cartridges thcreagainst for centering said divider between the blocking and release positions to open said chambers for loading the cartridges therein- 5. The magazine as defined in claim 4 wherein said slide includes a tang arranged for contact with said finger when said divider is in the operative position to releasably block said divider in the blocking position, and arranged to be free of said finger through displacement of said slide by said follower in said primary chamber when the last one of the cartridges in said primary chamber is picked up by the bolt.

6. The magazine as defined in claim 5 wherein said follower in said primary chamber is contoured commensurate with said first side upper curved portion and said divider to permit overtravel of said follower towards said mouth after the last one of the cartridges in said primary chamber is picked up by the bolt, and said lug on said follower in said primary chamber is located thereon to actuate said slide for sufficient displace ment during the overtravel to displace said tang of said finger for release of said divider.

7. The magazine as defined in claim 5 wherein said divider is provided along the top thereof with a first edge arranged for cooperation with said upper curved portion of said first side to successively retain the cartridges in said primary chamber at tion, and said first edge and said second edge being related to said upper curved portions so as to release the cartridges in said secondary chamber and successively retain the cartridges therein in position for pickup by the bolt when said divider is in the release position. 

1. A cartridge magazine for a firearm having a reciprocal bolt comprising, a case divided into a primary chamber and a secondary chamber, each of said chambers being adapted to hold a double stack of cartridges in staggered arrangement, self-contained means for successively positioning the cartridges for pickup by the bolt, and a partition for separating said primary and secondary chambers, said partition including a divider section mounted to said case for pivotal displacement about one axis to a position opening said chamber simultaneously for loading the cartridges thereinto and for rotational displacement about another axis normal to said one axis to releasably retain the cartridges in said secondary chamber until those in said primary chamber are entirely removed therefrom.
 2. The magazine as defined in claim 1 wherein said case comprises a first side related to said primary chamber and a second side related to said secondary chamber, said sides each including an upper portion curving upwardly and inwardly to form therebetween a mouth arranged to successively receive the cartridges from said chambers for pickup by the bolt, and including a spring-pressed follower disposed in each of said chambers for biasing the cartridges therein towards said mouth, a partition separating said primary and secondary chambers, a divider section of said partition displaceably mounted in said case for cooperation with said upper portions to successively position the cartridges in said primary chamber at said mouth for pickup by the bolt and simultaneously hold the cartridges in said secondary chamber away from contact by the bolt until those in said primary chamber are entirely removed therefrom and to open the adjacent ends of said compartments for loading the cartridge into, and means cooperating with said divider to release the cartridges from said secondary chamber for successive pickup by the bolt when those in said primary chamber are entirely removed therefrom.
 3. The magazine as defined in claim 3 wherein said last means cooperating with said divider comprise a slide displaceably mounted on said case so as to releasably hold said divider in an operative position relative to said upper portions for retaining the cartridges in said secondary chamber until those in said primary chamber are entirely removed therefrom, and a lug on said follower in said primary chamber arranged to displace said slide for release of said divider when the last cartridge in said secondary chamber is picked up by the bolt to permit rotational displacement of said divider by the bias of the cartridges in said secondary chamber thereagainst to release the cartridges therein for successive pickup by the bolt at said mouth.
 4. The magazine as defined in claim 3 and including means for mounting said divider for pivotal displacement about one axis between the operative position and a lower depressed position and for rotational displacement about another axis normal to said one axis between a blocking position wherein the cartridges in said secondary chamber are blocked by said divider from displacement to said mouth for pickup by the bolt when said divider is also in the operative position and a release position wherein the cartridges in said secondary chamber are released by said divider for displacement to said mouth, spring means cooperating with said divider for biasing said divider to the operative position, a finger extending from said divider for reception by an opening in said case, an upper portion of said opening cooperating with said finger for limiting rotational displacement of said divider between the blocking and release positions when in the operative position, and a pocket portion of said opening disposed for receiving said finger when said divider is actuated to the depressed position by downward pressure of the cartridges thereagainst for centering said divider between the blocking and release positions to open said chambers for loading the cartridges thereinto.
 5. The magazine as defined in claim 4 wherein said slide includes a tang arranged for contact with said finger when said divider is in the operative position to releasably block said divider in the blocking position, and arranged to be free of said finger through displacement of said slide by said follower in said primary chamber when the last one of the cartridges in said primary chamber is picked up by the bolt.
 6. The magazine as defined in claim 5 wherein said follower in said primary chamber is contoured commensurate with said first side upper curved portion and said divider to permit overtravel of said follower towards said mouth after the last one of the cartridges in said primary chamber is picked up by the bolt, and said lug on said follower in said primary chamber is located thereon to actuate said slide for sufficient displacement during the overtravel to displace said tang of said finger for release of said divider.
 7. The magazine as defined in claim 5 wherein said divider is provided along the top thereof with a first edge arranged for cooperation with said upper curved portion of said first side to successively retain the cartridges in said primary chamber at said mouth for pickup by the bolt when said divider is in the blocking position, and with a second edge arranged for cooperation with said upper curved portion of said second side to block upward displacement of the cartridges in said secondary chamber to a position in said mouth for successive pickup by the bolt when said divider is in the blocking position, and said first edge and said second edge being related to said upper curved portions so as to release the cartridges in said secondary chamber and successively retain the cartridges therein in position for pickup by the bolt when said divider is in the release position. 